A guard of flowers stands at its doors. More than a thousand points of support hold up its concrete walls and titanium shell.

The slabs, stones, and cobblestones lining its interior number in the thousands. Almost 25 years have passed since the Guggenheim Museum opened, and it continues to shine on the southern banks of Bilbao’s waterway. It is a symbol of the city’s transition, captivating a million visitors each year.

Behind its doors lies an artistic treasure. Its vast collection includes works from the Guggenheim headquarters in New York and other pieces from various international museums and temporary exhibitions. Art also decorates the exterior. Puppy, the leafy dog sculpture designed by Jeff Koons, and Mamá, the large metal spider by Louise Bourgeois, are two prominent examples.

Beyond its artistic value, the Guggenheim Museum is an icon of architecture and engineering. Built by Ferrovial from 1992 to 1997, this whimsical building would be impossible without its solid bones. Its foundations consist of 665 concrete piles that sink an average of 14 meters into the ground, along with 444 pile caps and 181 micro-piles.

All of this supports a maze of rooms and exhibition spaces sheltered by 42,000 titanium tiles and 14,500 square meters of stone. Its walls add some 60,000 cubic meters of formwork. They’re supported by over 3,000 tons of metal armor and more than 1,500 meters of concrete beams.

The quirky architectural dreams that made this museum so iconic mean that no two pieces are the same in its metal frame. Every one is tailor-made to fuse art and physics in its design.